Core CMake: minor improvements. - switched from PROJECT_SOURCE_DIR to CMAKE_CURRENT_LIST_DIR - introduced SPIRIT_COMPILE_DEFINITIONS which are applied to core library and c++ tests - set CUDA language property on some test sources
Core CMake: minor improvements.
- switched from PROJECT_SOURCE_DIR to CMAKE_CURRENT_LIST_DIR
- introduced SPIRIT_COMPILE_DEFINITIONS which are applied to core library and c++ tests
- set CUDA language property on some test sources

spirit-code/spirit,spirit-code/spirit,spirit-code/spirit,spirit-code/spirit,spirit-code/spirit,spirit-code/spirit